91-24-08: Outboard Flaps

91-24-08 McDONNELL DOUGLAS: Amendment 39-8094. Docket No. 91-NM-221-AD. \n\n\tApplicability: Model MD-11 series airplanes, certificated in any category. \n\n\tCompliance: Required as indicated, unless previously accomplished. \n\n\tTo prevent fatigue cracking and possible structural failure of the outboard flaps, accomplish the following: \n\n\t(a)\tPrior to the accumulation of 400 landings, or within 30 days after the effective date of this AD, whichever occurs later, perform a borescope inspection to detect cracks in the left and right outboard flap inboard and outboard closure rib spindle support fittings, in accordance with Paragraph 2, "Accomplishment Instructions," of McDonnell Douglas Alert Service Bulletin A57-15, Revision 2, dated October 28, 1991 (hereinafter referred to as the Service Bulletin). \n\n\t(b)\tWithin 30 days after the effective date of this AD, perform a visual inspection for cracks and delamination of the upper skin of the outboard flaps in accordance with the Service Bulletin. \n\n\t(c)\tIf no cracking or delamination is found as a result of the inspections required by paragraphs (a) and (b) of this AD, accomplish either subparagraph (c)(1) or (c)(2) of this AD: \n\n\t\t(1)\tRepeat the borescope inspections of the spindle support fittings required by paragraph (a) of this AD at intervals not to exceed 400 landings; and repeat the visual inspections of the upper skin required by paragraph (b) of this AD at intervals not to exceed 60 days. In cases where no cracking is found, the accomplishment of the modification shown in Figures 3 and 4 and described in Tables I and II of the Service Bulletin constitutes terminating action for the repetitive inspections required by this paragraph. Or \n\n\t\t(2)\tPrior to further flight, accomplish the modification shown in Figures 3 and 4 and described in Tables I and II of the Service Bulletin. \n\n\t(d)\tIf a crack with a length of less than 1 inch is found in the spindle support fitting as a result of the borescope inspections required by paragraphs (a) or (c)(1) of this AD, accomplish either subparagraph (d)(1) or (d)(2) of this AD: \n\n\t\t(1)\tPrior to further flight, accomplish the modification shown in Figures 3 and 4 and described in Tables I and II of the Service Bulletin. In cases where such cracking is found, this modification is considered to be an interim (temporary) action only. Or \n\n\tNOTE: The FAA is considering further rulemaking to require the accomplishment of a permanent repair. \n\n\t\t(2)\tPrior to further flight, incorporate a permanent repair in a manner approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. The accomplishment of this permanent repair constitutes terminating action for the repetitive inspections required by paragraph (c)(1) of this AD. \n\n\t(e)\tIf a crack with a length of greater than 1 inch is found in the spindle support fitting as a result of the borescope inspections required by paragraph (a) or (c)(1) of this AD, prior to further flight, accomplish a permanent repair in a manner approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. Accomplishment of this permanent repair constitutes terminating action for the repetitive inspections required by paragraph (c)(1) of this AD. \n\n\t(f)\tIf cracks or delamination are found in the skin as a result of the inspections required by paragraph (b) of this AD, prior to further flight, accomplish the modification shown in Figures 3 and 4 and described in Tables I and II of the Service Bulletin. Accomplishment of this modification constitutes terminating action for the repetitive inspections required by paragraph (c)(1) of this AD. \n\n\t(g)\tAn alternative method of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate.NOTE: The request should be forwarded through an FAA Principal Maintenance Inspector (PMI), who may concur or comment and then send it to the Manager, Los Angeles ACO. \n\n\t(h)\tSpecial flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base in order to comply with the inspection requirements of this AD. \n\n\t(i)\tThe inspection and modification requirements shall be done in accordance with McDonnell Douglas MD-11 Alert Service Bulletin A57-15, revision 2, dated October 28, 1991. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies may be obtained from McDonnell Douglas Corporation, Technical Publications-Technical Administrative Support, C1-L5B, 3855 Lakewood Boulevard, Long Beach, California 90846. Copies may be inspected at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 1601 Lind Avenue S.W., Renton, Washington; or at theLos Angeles Aircraft Certification Office, 3229 East Spring Street, Long Beach, California; or at the Office of the Federal Register, 1100 L Street N.W., Room 8401, Washington, D.C. \n\n\tThis amendment (39-8094, AD 91-24-08) becomes effective on December 12, 1991.